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光电探测器(PDIC)的安装误差导致光学头的光学轴心与光电探测器的中心不重合。在光盘标量衍射模型的基础上,引入光电探测器的位置误差参数,根据DVD-ROM的盘片参数,计算并分析了位置误差对差动相位探测(DPD)信号的影响。计算结果表明:沿盘片切向的位置误差使DPD的幅值变小,在25%的范围内DPD的幅值随切向位置误差的变化系数为1.52T;沿盘片径向的位置误差使DPD产生直流偏置,在50%的范围内DPD直流偏置随径向位置误差的变化系数为3.8T。
The installation error of the photodetector (PDIC) causes the optical axis of the optical pickup to not coincide with the center of the photodetector. Based on the scalar diffraction model of the optical disc, the position error parameters of the photodetector are introduced, and the influence of the position error on the differential phase detection (DPD) signal is calculated and analyzed according to the disc parameters of the DVD-ROM. The calculated results show that the DPD amplitude decreases along the tangential direction of the disc, and the variation coefficient of the amplitude of the DPD with the tangential position error within 25% is 1.52T. The position error along the disc radial direction The DC offset of DPD is generated, and the variation coefficient of DPD DC offset with radial position error within the range of 50% is 3.8T.